how do I figure the cost of watts?

BFL13 wrote:
Does the power company charge for KWH or KVAH? Does the KillaWatt measure KW or KVA (some can measure PF, ISTR) We don't want to compare prices using different amounts. Does it come out right with lights but not dryers? (Of course I am only asking in the true spirit of inquiry )

It depends, large industries are charged KVAH and are encouraged to power factor correct.

Most households are charged KWH and have their rate adjusted for what is considered an average or normal power factor load.

This is all changing though due to the high displacement power factor loads that are generated by CFL's, LED's, TV's, and other electronic systems.

Hi BFL13,

They charge by kwh, in Saskatchewan. However for commercial sites they also charge based on peak demand.

Does the power company charge for KWH or KVAH? Does the KillaWatt measure KW or KVA (some can measure PF, ISTR) We don't want to compare prices using different amounts. Does it come out right with lights but not dryers? (Of course I am only asking in the true spirit of inquiry )

DryCamper11 wrote:

ken white wrote:
Tough crowd, and I know all of the conversions... :B

The engineer in me likes to reinforce SI units since they are used almost everywhere in the world.

From having read your many informative posts, I know you know them, and I wasn't really just yanking your chain :)

I was actually trying to point out how closely the commonly used KWH energy units are to the SI Joule energy units you were referring to.

It's the fact that the common unit and the SI unit are basically the same, which brought about my post. That close relationship is relatively unusual, since most commonly used units in the U.S. are not related to SI units: miles, feet, inches, BTU, degrees F, etc.

A Joule is a watt-second so the commonly used KWH is directly obtainable by knowing the number of seconds in an hour (3600=60*60) and the number of watts in a kilowatt (1000) to get the 3.6 megajoules = 1 KWH conversion.

I'm just busting on you, and I know you know your stuff as well. Take care and keep the helpful post coming!

:)

Wow . . . thanks again DryCamper11. I'll certainly give that a try.

jcpainter wrote:
Thank you drycamper11. If they truly will give a total usage for the time they were plugged in, that would work perfectly for determining the cost to dry clothes for 1 hr, 2 hrs, etc.

Much appreciated.

The Kill-A-Watt will do the job, but I also looked at the link you provided to this device you previously purchased and AFAICT, it it looks like it will also do what you want, with a bit of fooling around.

I read the manual and it says it starts with the instantaneous watts being used, but after 45 minutes, it switches to an averaging mode for the cost.

Here's how you can use it:

Plug it in and run the dryer through one cycle. Wait one full day and then press the cost button. The cost button will then tell you what it would cost to run the dryer every day for a month or every day for a year. Divide by the number of days in a month or year to get the cost of one run. It assumes a 30 day month and a 365 day year. You could also check the cost after 2 hours, and it will assume you run it 12 times a day, so divide the month cost by 360 (12 times 30).

The above method sort of assumes that your dryer does not draw power when you aren't running a cycle (e.g. it does not have a clock or timer or something else that uses power). (It adds in the cost of a day of being off whatever that cost is) You can find out easily if it has phantom drain power usage by just pressing the watt button when the dryer's off. If it shows zero, it doesn't draw power when off.

If it does draw power when off, you'd have to figure out how much and factor in the cost of that power draw (if you leave it plugged in when not in use - or subtract that drain cost if you unplug it after each use) to get an accurate number for usage cost over month/year. It's not hard, but it's probably more work than needed.

I like the Kill-A-Watt, particularly when measuring the voltage and frequency of a generator or the voltage in an RV park pedestal, but since you already have a device, you can make use of it if you want.

I hope this helps.

(sigh)

opnspaces wrote:
Can you help me figure this out. I know it should be fairly simple but I just don't seem to get it.

Thanks

You are working WAY TOO HARD.

The Kill-A-Watt 4400 has a button on the way left that will show you the total KwHr consumed as long as you don't unplug it. So, plug it in and run it for a known regular period. Read the total, and multiply by your cost.

If you have a model 4460, then you should plug it in and enter your KwHr cost, then run whatever and read the number it gives you.

Matt

Lynnmor wrote:

Francesca Knowles wrote:

opnspaces wrote:
Can you help me figure this out. I know it should be fairly simple but I just don't seem to get it.

I stopped tryin' to smarten up ages ago...who needs to know how to do the math when there's an online tool to do so! :B

The STUPID link is broken.

:S
Fixed now...that'll teach me to test links before posting...fortunately, Roy Ken got it right downpage!

RoyB wrote:
Here's a good link to a calculator per day..

CALC

Roy Ken

jcpainter wrote:
Thanks for the formulas. We purchased one of the devices that you plug into the wall and then plug the appliance into like this . . . expecting to learn how much energy the appliance uses in a given amount of time.

For example, how much does it cost to dry clothes in the Splendide 110 dryer for 2 hours? Is it a reasonable cost, or should I go to the trouble to hang them on the line?

The device is worthless for that. It will give a watt reading, but doesn't have any type of timer to see how much it used during the usage of the appliance. It gives you monthly estimates (based on the cost of electric that you enter) but who runs the dryer for a month?

Does anyone actually own a device like this that meters the usage of an appliance for the time the appliance is used?

I've used a basic Kill-a-Watt to learn the cost of running devices that use electricity intermittently like, for instance, a refrigerator.

I plug it in then set an alarm on my phone to check the reading every 24 hours. The Kill-a-Watt totals the watts used until it's unplugged. If I miss a day it's no problem - I'm going to use an average anyway. IIRC I went six days with the refrigerator and got a good idea what the average daily usage was.

If you want to know what it costs to dry a load of clothes just plug it in when you start then check the total wattage used when the load is done.